The present invention relates to an electronic musical instrument with automatic performance function, constructed not only to generate a musical sound in response to operation of an input implement such as a keyboard, but also to undergo automatic performance of a given musical composition composed of plural parts according to performance data recorded in a memory.
In some conventional electronic musical instruments having automatic performance function, a semi-automatic performance can be effected to selectively silence a certain one of the plural parts of the musical composition, while a player conducts a manual performance of the silenced part in synchronization with the remaining sounded parts. By such operation, automatic performance of a rather mechanical nature may be modified to add a human touch. Further, in practicing a certain part, the player can readily recognize if the certain part is actually mastered without notes. Such a technique of selectively silencing a desired part of the automatic performance is called "minus-one performance" or "minus play". This technique is disclosed, for example, in Japanese Patent Application Laid-Open No. 321480/1989. In this prior art, a specific switch is provided to select a particular part of the performance data corresponding to one of upper, lower and foot keyboards to effect the minus-one performance.
However, the conventional electronic musical instrument utilizes a function selecting switch to change between the minus-one performance and the regular or full automatic performance. Therefore, once the minus-one performance is selected and set, a certain part designated in minus play is continuously held in a silenced state. The conventional instrument is at a disadvantage in that the function selecting switch must be actuated during the course of the minus-one performance in order to recover the silenced state of the designated part. For instance, when practicing the designated part using the minus-one performance, if the player incidentally wants to hear the designated part, due to lack of score memory for example, the player must actuate the function selecting switch to restore the designated part immediately after incidental play discontinuation of the designated part.